Fix Linux hang on shutdown (#4617)

* Rework StdErr-to-log redirection to use built-in FileStream, and do reads asynchronously to avoid hanging the process shutdown.

* set _disposable to false ASAP

Ryujinx.Common/SystemInterop/StdErrAdapter.cs

@@ -1,18 +1,21 @@
+using Microsoft.Win32.SafeHandles;
 using Ryujinx.Common.Logging;
 using System;
 using System.IO;
 using System.Runtime.InteropServices;
 using System.Runtime.Versioning;
 using System.Threading;
+using System.Threading.Tasks;
 
 namespace Ryujinx.Common.SystemInterop
 {
     public partial class StdErrAdapter : IDisposable
     {
         private bool _disposable = false;
-        private UnixStream _pipeReader;
-        private UnixStream _pipeWriter;
-        private Thread _worker;
+        private Stream _pipeReader;
+        private Stream _pipeWriter;
+        private CancellationTokenSource _cancellationTokenSource;
+        private Task _worker;
 
         public StdErrAdapter()
         {
@@ -31,37 +34,39 @@ namespace Ryujinx.Common.SystemInterop
             (int readFd, int writeFd) = MakePipe();
             dup2(writeFd, stdErrFileno);
 
-            _pipeReader = new UnixStream(readFd);
-            _pipeWriter = new UnixStream(writeFd);
+            _pipeReader = CreateFileDescriptorStream(readFd);
+            _pipeWriter = CreateFileDescriptorStream(writeFd);
 
-            _worker = new Thread(EventWorker);
+            _cancellationTokenSource = new CancellationTokenSource();
+            _worker = Task.Run(async () => await EventWorkerAsync(_cancellationTokenSource.Token), _cancellationTokenSource.Token);
             _disposable = true;
-            _worker.Start();
         }
-
+        
         [SupportedOSPlatform("linux")]
         [SupportedOSPlatform("macos")]
-        private void EventWorker()
+        private async Task EventWorkerAsync(CancellationToken cancellationToken)
         {
-            TextReader reader = new StreamReader(_pipeReader);
+            using TextReader reader = new StreamReader(_pipeReader, leaveOpen: true);
             string line;
-            while ((line = reader.ReadLine()) != null)
+            while (cancellationToken.IsCancellationRequested == false && (line = await reader.ReadLineAsync(cancellationToken)) != null)
             {
                 Logger.Error?.PrintRawMsg(line);
             }
         }
-
+        
         private void Dispose(bool disposing)
         {
             if (_disposable)
             {
+                _disposable = false;
+                
                 if (OperatingSystem.IsLinux() || OperatingSystem.IsMacOS())
                 {
+                    _cancellationTokenSource.Cancel();
+                    _worker.Wait(0);
                     _pipeReader?.Close();
                     _pipeWriter?.Close();
                 }
-
-                _disposable = false;
             }
         }
 
@@ -74,11 +79,11 @@ namespace Ryujinx.Common.SystemInterop
         private static partial int dup2(int fd, int fd2);
 
         [LibraryImport("libc", SetLastError = true)]
-        private static unsafe partial int pipe(int* pipefd);
+        private static partial int pipe(Span<int> pipefd);
 
-        private static unsafe (int, int) MakePipe()
+        private static (int, int) MakePipe()
         {
-            int *pipefd = stackalloc int[2];
+            Span<int> pipefd = stackalloc int[2]; 
 
             if (pipe(pipefd) == 0)
             {
@@ -89,5 +94,16 @@ namespace Ryujinx.Common.SystemInterop
                 throw new();
             }
         }
+        
+        [SupportedOSPlatform("linux")]
+        [SupportedOSPlatform("macos")]
+        private static Stream CreateFileDescriptorStream(int fd)
+        {
+            return new FileStream(
+                new SafeFileHandle((IntPtr)fd, ownsHandle: true),
+                FileAccess.ReadWrite
+            );
+        }
+       
     }
 }

Ryujinx.Common/SystemInterop/UnixStream.cs

@@ -1,155 +0,0 @@
-using System;
-using System.IO;
-using System.Runtime.InteropServices;
-using System.Runtime.Versioning;
-
-namespace Ryujinx.Common.SystemInterop
-{
-    [SupportedOSPlatform("linux")]
-    [SupportedOSPlatform("macos")]
-    public partial class UnixStream : Stream, IDisposable
-    {
-        private const int InvalidFd = -1;
-
-        private int _fd;
-
-        [LibraryImport("libc", SetLastError = true)]
-        private static partial long read(int fd, IntPtr buf, ulong count);
-
-        [LibraryImport("libc", SetLastError = true)]
-        private static partial long write(int fd, IntPtr buf, ulong count);
-
-        [LibraryImport("libc", SetLastError = true)]
-        private static partial int close(int fd);
-
-        public UnixStream(int fd)
-        {
-            if (InvalidFd == fd)
-            {
-                throw new ArgumentException("Invalid file descriptor");
-            }
-
-            _fd = fd;
-            
-            CanRead = read(fd, IntPtr.Zero, 0) != -1;
-            CanWrite = write(fd, IntPtr.Zero, 0) != -1;  
-        }
-
-        ~UnixStream()
-        {
-            Close();
-        }
-
-        public override bool CanRead { get; }
-        public override bool CanWrite { get; }
-        public override bool CanSeek => false;
-
-        public override long Length => throw new NotSupportedException();
-
-        public override long Position
-        {
-            get => throw new NotSupportedException();
-            set => throw new NotSupportedException();
-        }
-
-        public override void Flush()
-        {
-        }
-
-        public override unsafe int Read([In, Out] byte[] buffer, int offset, int count)
-        {
-            if (offset < 0 || offset > (buffer.Length - count) || count < 0)
-            {
-                throw new ArgumentOutOfRangeException();
-            }
-
-            if (buffer.Length == 0)
-            {
-                return 0;
-            }
-
-            long r = 0;
-            fixed (byte* buf = &buffer[offset])
-            {
-                do
-                {
-                    r = read(_fd, (IntPtr)buf, (ulong)count);
-                } while (ShouldRetry(r));
-            }
-
-            return (int)r;
-        }
-        
-        public override unsafe void Write(byte[] buffer, int offset, int count)
-        {
-            if (offset < 0 || offset > (buffer.Length - count) || count < 0)
-            {
-                throw new ArgumentOutOfRangeException();
-            }
-
-            if (buffer.Length == 0)
-            {
-                return;
-            }
-
-            fixed (byte* buf = &buffer[offset])
-            {
-                long r = 0;
-                do {
-                    r = write(_fd, (IntPtr)buf, (ulong)count);
-                } while (ShouldRetry(r));
-            }
-        }
-
-        public override long Seek(long offset, SeekOrigin origin)
-        {
-            throw new NotSupportedException();
-        }
-
-        public override void SetLength(long value)
-        {
-            throw new NotSupportedException();
-        }
-
-        public override void Close()
-        {
-            if (_fd == InvalidFd)
-            {
-                return;
-            }
-
-            Flush();
-
-            int r;
-            do {
-                r = close(_fd);
-            } while (ShouldRetry(r));
-
-            _fd = InvalidFd;
-        }
-
-        void IDisposable.Dispose()
-        {
-            Close();
-        }
-
-        private bool ShouldRetry(long r)
-        {
-            if (r == -1)
-            {
-                const int eintr = 4;
-
-                int errno = Marshal.GetLastPInvokeError();
-
-                if (errno == eintr)
-                {
-                    return true;
-                }
-
-                throw new SystemException($"Operation failed with error 0x{errno:X}");
-            }
-
-            return false;
-        }
-    }
-}